The overall objective of this project is to study the regulation of carbohydrate and lipid metabolism during perinatal development in mammalian liver and to generate significant information using an animal model which will enhance understanding of metabolic aspects of neonatal hypoglycemia and related metabolic disorders associated with development. This study will focus on three major areas: 1) assessment of the enzymatic changes in the pathways of glucose production in liver and kidney during the perinatal period, 2) evaluation of the mechanisms of hormonal control of glucose synthesis in the newborn, and 3) quantitation of the physiological significance of the compartmentation of phosphoenolpyruvate carboxykinase, a specific regulatory enzyme on the pathway of gluconeogenesis. Metabolic processes such as gluconeogenesis and ketogenesis will be measured in isolated liver parenchymal cells andrenal tubules. The significance of enzyme compartmentation in neonatal glucose synthesis will be measured in isolated hepatocytes with the aid of specific inhibitors of gluconeogenesis. The concentrations of metabolic intermediates will be measured spectrophotometrically or fluorometrically.